Friday, September 14, 2007

The San Diego Saga

The City of San Diego (California) is a widely cited case-study regarding the unsuccessful implementation of an indirect potable water recycling (IPR) scheme. Ironically, it is also an important case-study for where some of the best science has been conducted to establish and demonstrate the safety of the practice.

San Diego is often credited with the popularisation of the intentionally yuck-inducing term ‘toilet-to-tap’. An article from CNN in 1997 stated "If all goes according to plan, by the year 2001, the city's sewage water will be treated and recycled right into the drinking tap". Hence intentionally emotive language, crafted to emphasise a link between sewage and taps can be traced back at least a decade. Perhaps not surprisingly a highly emotional debate ensued.

The plan in San Diego was to pipe highly treated municipal effluent to the San Vicente Reservoir, where it would mix with raw river water and become part of the city’s raw water supply. This proposal met with considerable community opposition; apparently largely on the basis that IPR seems distasteful. However, an editorial from the Sacramento Bee puts some of the issues in perspective:

"Alas, it seems time to let San Diegans and any other squirming citizens in on a little secret about water supplies: Toilet-to-tap is as old as civilization in California. And if San Diego shuns blended toilet water, it's about to become very thirsty.

With little groundwater underneath it, San Diego has two primary supplies. One is the Sacramento-San Joaquin Delta. The other is the Colorado River. The proposed project, to reuse water rather than drain it into the ocean, is one viable way to create a reliable local supply for San Diego. But it does involve the blending of treated water with untreated water in a reservoir. Technically, this means drinking treated toilet water. Is this really new for San Diego or most cities? Of course not.

Consider the Sacramento and San Joaquin rivers, whose waters San Diego draws from the Delta. More than 300 farmers and cities are permitted to discharge their treated and untreated runoff into these rivers. Counties empty treated sewage water into rivers every day. Almost 10 percent of the average flow of these rivers is discharge, according to San Diego's water department.

Yuck? Consider the Colorado River. Las Vegas dumps 58 billion gallons of treated sewage water into nearby Lake Mead, from whence it flows into the Colorado. More than 17 percent of this river's flow is discharge. Guess who drinks some of this, San Diego?"

Although IPR is not current San Diego City policy, it seems the issue will not disappear until long-term water shortages are resolved. The city’s Union-Tribune newspaper today reported on an on-going disagreement between the San Diego Mayor Jerry Sanders and City Attorney Michael Aguirre.

Mayor Sanders has publicly rejected IPR for San Diego, while Attorney Aguirre has pointed out that “we rely on recycled water right now…We import recycled water from the Colorado River”. The Union-Tribune stated that Attorney Aguirre accused the mayor of relying on polls to dictate his water policies and not educating the public.

It’s certainly not for me to suggest how San Diego should best manage its water and I don’t pretend to have any capacity to be able to do so. However, it is insightful to observe the debate and consider just how significant politics and populism are in the determination of long-term infrastructure planning.


Anonymous said...

Its a shame that Queensland doesnt have any ethical mayors like San Diego is lucky to have. Quite a contrast to Mayor Thorely. Thorely and the QLD government are perfectly happy for us to be participants in a crazy intergenerational health experiment! The good citizens of San Diego must be rolling on the floor laughing at us.

San Diego said...

And if San Diego shuns blended toilet water, it's about to become very thirsty.

One word - desalination.

Stuart Khan said...

Hi ‘San Diego’,

Indeed, desalination is always an option for California and I expect to see some fairly significant increases in desal capacity there during the next couple of decades.

However, I think the author of the Sacramento Bee article may have been making the point that practically all of San Diego’s current water supplies include recycled water. Thus if the citizens truly want to shun recycled water, then they will need to shun their current supplies. While desal is an obvious option, I think it is an unlikely solution to provide the city’s entire water supply.

Stuart Khan said...

This recent article from the 'Voice of San Diego' is interesting.

It states that Mayor Sanders does "not dispute the science that shows recycling sewage can be a safe source of drinking water".

Instead, his primary concern appears to be related to costs. This apparently includes the cost of the necessary treatment, -upgrading from a system that dumps primary treated effluent into the Pacific Ocean, and the “costs of educating the public”.

Hmmm…are Californian’s assumed to be particularly challenging to “educate”? Is education not worth some investment?

Sanders: Reuse Too Expensive
Thursday, September 13, 2007

Mayor Jerry Sanders said today that he will not support a plan to augment the city's reservoirs with treated sewage, a plan that City Attorney Mike Aguirre has attempted to revive as a potentially valuable new water source.

The mayor said he would oppose any efforts to begin recycling the city's sewage, saying that the technology to do so was too expensive and not supported by city residents.

Sanders said he would not revisit the issue if water cutbacks from the Sacramento-San Joaquin River Delta are more severe than projected. A federal judge in Fresno issued a ruling Aug. 31 that water suppliers say could reduce exports from the delta by 37 percent next year. The mayor said the timeframe of implementing water reuse wouldn't help bridge any short-term water supply gaps.

"It's clearly a long-term issue," Sanders said. "It's not something I'm going to address at all over the next several years."

Sanders did not dispute the science that shows recycling sewage can be a safe source of drinking water. Millions of gallons of treated sewage are dumped into the Colorado River upriver from San Diego's pumps. But the mayor said the costs of educating the public and building necessary infrastructure would make recycled water too expensive.

In a report, the Mayor's Office estimated that recycled water would cost between $1,600 and $1,882 for each acre foot -- a measurement equal to an acre of land covered in a foot of water (or about 326,000 gallons.)

The city's supply of drinking water costs about a third: $679 per acre foot.

"This is not a cost-efficient alternative," Sanders said.

Aguirre, who held a press conference after the mayor, did not dispute the higher cost. But he said the importance of securing San Diego's water supply, which is largely reliant on imported sources of water from the Colorado River and Sacramento-San Joaquin River Delta, should trump the additional costs.

"If it costs us money to gain a level of water independence," Aguirre said, "I think it's money well-spent."


Stuart Khan said...

It seems like the San Diego IPR scheme is indeed back on the table. This update (below) suggests significant interest from the city council in revisiting previously abandoned plans.

I have only pasted part of the article here. Click on the link for the full story.

With Water Scarce, Council Recycles Water Recycling

Faced with bad news about the future of the region's water supply, council agrees (again) to consider reusing wastewater.

By ROB DAVIS, Voice Staff Writer
Tuesday, Oct. 9, 2007

San Diego's flirtation with recycling its wastewater is officially back for a fourth time.

As the region faces its most serious water supply restrictions in more than a decade, the City Council agreed to once again consider a plan to boost drinking reservoirs with treated wastewater.

At a Monday meeting, the council voted unanimously to hear a presentation on its 2006 water recycling study when it meets later this month. Though the study was completed early last year, the council was never briefed on its findings.

That study outlined several alternatives for expanding the city's use of recycled water -- primarily to boost irrigation and to fill city reservoirs with treated wastewater. But Mayor Jerry Sanders has opposed water recycling, saying it is too expensive and not favored by the public.

Water recycling has been considered by council members periodically for eight years. In 1999, the City Council halted studies after critics famously dubbed the program "toilet to tap." A council committee revived the issue in 2003 at the behest of environmentalists -- a move that led to the study now headed to the council.

Council members said they wanted to hear more about the recycling practice after hearing a report Monday on the precariousness of the region's water supply. Currently, about 2 percent of the region's water comes from recycled sources.

"Any water you're drinking is 'toilet to tap,'" Councilman Jim Madaffer said. "We only have so much water. Only so much exists. H2O is a molecule. And it's been the same amount since the planet was formed. It's important that we really hear this water reuse study."

Environmentalists urged the council to push forward with the proposal and suggested a implementing a one-year demonstration project as an interim step.

"We have the obligation to use that water as wisely as humanly possible," said Bruce Reznik, executive director of San Diego Coastkeeper. "That's something in San Diego that we haven't done."

(see source for full article).

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